4 Check Engine Codes come and go. Odometer and Cruise not working.

[InterAce2]

Hello,

I love this car and want to get it working well, I greatly appreciate any and all help.

2004 S80 T6 Twin Turbo.

I have some engine codes that come on and then go off.

When I fill the tank all the way up the car throws codes P0496 EVAP System High Purge Flow, and P0497 EVAP system Low Purge Flow. the MIL is ON at this point always. After driving down the gas level to just below half way, the MIL goes off and the codes go away. The car also is noticeably more responsive and faster with less than half a tank and no MIL.

Another problem occurs under boost. I will give it gas on the freeway to pass someone, and the boost seems to surge and then slow. It like its fluttering or boosting on, off, on, off, you can feel it like pulsing with speed and a slight inconsistent acceleration feeling. This only happens when I hold the gas down for more than a couple of seconds.

Also there a code that seems to always come up P0507 Idle Control System RPM - Higher than expected. I have no idea, or dont see any symptoms about this yet.

On the dash it has a warning "Brake Failure Stop Safely". However the brakes work OK. Code P0571 Brake Switch A Circuit is always on or pending.

Odometer is basically not working.. it will go up like 1 mile for every 100 driven. Cruise Control Not working.

Also when the AC compressor kicks on at a stop the car wants to lurch forward.

Thanks.

[Engineeringdad]

If you still have the 2004 S80 T6 Twin Turbo I can help you through all these issues.(or anyone else reading this post)
I'm a Master Mechanical Engineer, not in automotive but in ME related to any all mechanical functionalities, but nevertheless the basic fundamental apply. I have a 2004 Volvo S80 T6 2.9L Executive series, my "Problem Child". I've broken down, troubleshooted, repaired and diagnosed every inch, every part on my Volvo imageable. The problems and codes your listing are a staple of issues with the 1999-2006. If you want you can contact me directly and I can give you the proper steps to correct all the issues you listed. My name: Jerry
My email: [email protected]
My Phone: I'll give in the email request

Some Brief Answers

Codes P0496 EVAP System High Purge Flow, and P0497 EVAP system Low Purge Flow.
A. Purge Valve also plays a part in your Turbo Under boost Issues. See answer in Code P0299

Code P0299 Under Boost
A. That a Air Pressure Issue (forced air) Start first by "Looking" for the 1/4 Hose connection coming off the two center plastic air tubes coming from the turbos towards the radiator.

1. There's a 1/4" hose port right (driver side) of the two molded plastic tubes, is the plastic nipple cracked that connects the rubber hose? If yes it can be re-glued, don't run out and buy any unnecessary parts (AutoZone for the plastic bonding adhesive) if NO then follow the 1/4" rubber line.
2. It go's to a "Pierburgs Turbocharger Boost Control Valve" then to the "Turbos Actuators Push Rod Control" on each Turbo. Is the complete air line assembly leaking past the Pierburgs? to include the metal air tubing assembly fasten to engines valve cover area between the two turbos? I'm not sure? how do I check, that seems complicated? Answer: (a) lets make it easy,pull the rubber hose off the Pierburgs Turbocharger Boost Valve (hose with yellow markings "no yellow marking found" then its the one on the bottom of the Pierburgs TBCV (b) check with hand held pump (brake bleed tool-it sells cheap-harbor freight) Did you lose vacuum in your test? if Yes then you isolated it from the Pierburgs connection to the turbos waste gate actuators. If NO then see 3.
3. The Pierburgs Turbocharger Boost Control Valve Can be defective. Do a bench/voltage test (it easy and simple to perform) Does it "clicks? (see YouTube Videos on the bench test. IF Yes then see 4.
4. The Actuators body might be leaking themselves or failing, you can un-connect the air lined from each actuator and apply 2-4 lbs. of air directly to see if the push rod arm moves forward. Note: they only work on pressure...not vacuum.

The complete air rail & hose assembly (off of the Pierburgs boost control) fittings & connections,
especially the dreaded Volvo metric Plastic "T" fitting is a guarantee leak.

Note: The two larger Air Tubes traveling across the engine are air output from air filter box to turbos air input. The two smaller tubes molded side-by-side going across the center of your engine are the forced air generated by the turbos, discharging the air at a higher volume and pressure to your Turbo Air Cooler (looks like a small radiator in your grill)...The engine exhaust powers the turbine wheel.

P0507 Idle Control System RPM - Higher than expected.
A. Volvos Number One Answer "Dirty throttle Body"
– Intake air leak (maybe)
– Poor electrical connection to the Intake Air Control (unlikely)
– IAC (possible) one of your hoses to the Oil Trap is Probably Disconnected or Failed (very possible)

Code P0571 Brake Switch A Circuit. "Brake Failure Stop Safely". However the brakes work OK.
A. Volvos Number One Brake/Traction Control/ABS Issues: It's Your ABS Brake Module - Defective Solder Joints.

1. You'll need to send Your ABS Brake Module Out to be Rebuild. The best company I've found in cost and workmanship is; Module Master $250.00 as of 06/02/23.https://modulemaster.com/
2. If you don't hear a click from the shifter area when placing your foot on the brake before shifting from park then your brake pedal switch is defective.
3. YOU CAN NOT SWITCH OUT your ABS Module with another Volvo ABS Module because the ECM (your cars computer) is programmed to the factory installed unit already in the car. The only way it will work is if purchase a brand new OEM Volvo ABS Module and have a Volvo dealership Service department Re-Flash/Re-Program the replacement unit, they will not re-program any after market or used ABS Modules....extremely expensive.

Odometer is basically not working.. it will go up like 1 mile for every 100 driven. Cruise Control Not working.
A. That's because of the Code P0571 Brake Switch A Circuit.

1. You'll need to send Your ABS Brake Module Out to be Rebuild. The best company I've found in cost and workmanship is; Module Master $250.00 as of 06/02/23.https://modulemaster.com/
2. If you don't hear a click from the shifter area when placing your foot on the brake before shifting from park then your brake pedal switch is defective.
3. YOU CAN NOT SWITCH OUT your ABS Module with another Volvo ABS Module because the ECM (your cars computer) is programmed to the factory installed unit already in the car. The only way it will work is if purchase a brand new OEM Volvo ABS Module and have a Volvo dealership Service department Re-Flash/Re-Program the replacement unit, they will not re-program any after market or used ABS Modules....extremely expensive.

Also when the AC compressor kicks on at a stop the car wants to lurch forward.??? Need More Imformation to answer.